1. Field of the Invention
This invention relates generally to identification systems, and especially relates to an identification system and method for gas detection instruments.
2. Brief Description of the Related Art
Gas detection instruments are utilized in industry to detect the presence and quantities of gases in a particular environment. In a certain segment of industry gas detection instruments are used to determined the presence and concentrations of harmful gases to which workers may be exposed while performing a variety of duties. Such duties include maintenance of equipment and facilities, inspections, calibrations, and other similar tasks. It is common that individuals perform these tasks in confined, or closed, spaces that may contain harmful gases. The gases may be given off as by-product of a controlled process or known source or may enter the closed space by way of a leak from an unknown source. In any event, it is common to protect workers from prolonged exposure to harmful gases by using a gas detection instrument which monitors for the presence of gases, concentrations of gases and time exposure to the gases.
Typically a gas detection instrument and information transfer system is used by individuals performing tasks where gases may be present. The information transferred to the instrument documents what individual uses the instrument (User ID) and where the instrument is used (Location ID). The information is only useful for prior art gas detection instruments that record gas exposures to non-volatile memory. A real time clock is typically incorporated into the design of data-logging models that provides a time-stamp for each recorded data point. Each time the instrument is turned on a new "session" is started and the User ID and Location ID are committed to memory along with the measured gas levels. The interval at which records are made is typically one minute but may vary from one second to one hour.
An important use of such detection systems is the ability to track and maintain long-term exposure records of certain gases for individual employees. These records are helpful in documenting compliance with worker-safety regulations as well as supportive evidence for workman's compensation claims. Another important use of such detection systems is recording and maintaining records for each location (man-holes, sewers, process vessels, electrical vaults, phone equipment vaults, etc.) so that gas levels may be observed and if abnormal levels of gases are detected on a regular basis in a particular location, remedial action can be taken.
A typical gas detection instrument, such as a Ph5 or PhD Lite manufactured by Biosystems Division of BACOU USA Safety Inc., is issued to an individual prior to entering a closed space which may contain a harmful gas. The gas detection instrument includes a data entry device wherein the individual, or user, inputs information specifying the user and further inputs information identifying the location where the detection instrument is to be used for a particular work session. An example of a prior art detection instrument includes a key pad wherein the user selects a user ID string and a location ID string from a list of such ID's stored in the memory of the instrument. In one such example an individual uses two of the keys to scroll down a list of alphanumeric choices and uses a third key to make a selection. In another prior art example a portable PC is used to input user and location information into the detection instrument. In such an embodiment, the PC is electrically connected to the instrument and a user selects a user ID string and a location ID string from a list of such ID's stored in memory on the PC and downloads the pertinent information in to the instrument.
One problem with the prior art detection instrument systems is that it is extremely easy for a user to input incorrect information. A user is required to navigate several menus and remember specific key stroke sequences to enter and/or activate the identification strings. As a result a user may incorrectly select the wrong user or location identification strings from the lists without knowing or having a way to verify or change the selection. Another problem with the prior art concerns the inability to easily add or change user or location identification strings. If the user or location is not preprogrammed into the instrument issued to a user the purpose of the detection instrument is obviated. In addition, the amount of information that may be transferred by prior art systems is extremely limited. An additional problem with the prior art concerns the systems that use a PC for downloading information to the instrument. In using such instruments, it becomes burdensome to transport and safely store the PC while a user performs the underlying tasks suggested herein above. In addition, the use of a PC requires increased skill levels of an operator and increases the cost of the detection instrument system.
In another detection instrument system of the prior art, a conventional bar code and wand is used to input user and location identification strings. In such systems, a bar code reader is connected to a detection instrument which is used to scan bar code labels pertaining to users and locations. Although bar code instruments eliminate some the problems present in other prior art detection systems, they too have many problems. One problem, similar to the PC systems, is that a bar code reader must be attached to and therefore transported along with, the detector. Another problem is that the bar code labels typically do not withstand some of the harsh environments in which these instruments are typically used. Reprogramming of bar coded labels is also difficult. Other problems, also common with PC linked detectors, the attachment of peripheral devices to the detector comprises the environmental integrity of the detector from a moisture ingression and radio-frequency interference susceptibility standpoint. This also creates an explosion hazard.
What is needed in the art is a reliable gas detection instrument identification system which increases accuracy, system flexibility, ease of use and one that functions well in harsh environments.